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CacheDependency.UtcLastModified Property

Definition

Namespace:
System.Web.Caching
Assembly:
System.Web.dll

Gets the time when the dependency was last changed.

public:
 property DateTime UtcLastModified { DateTime get(); };
public DateTime UtcLastModified { get; }
member this.UtcLastModified : DateTime
Public ReadOnly Property UtcLastModified As DateTime

Property Value

DateTime

The time when the dependency was last changed.

Examples

The following code example uses the AggregateCacheDependency class to add an item, with two CacheDependency object dependencies, to the Cache. When a request for the Cache item is made, the code checks whether the item is in the Cache. If it is, the UtcLastModified property is converted to a string and displayed on the page. If it is not, the item and its two dependencies are created and added to the Cache.

' When the page is loaded, use the 
' AggregateCacheDependency class to make 
' a cached item dependent on two files.

Sub Page_Load(sender As Object, e As EventArgs)
   Dim Source As DataView

   Source = Cache("XMLDataSet")

   If Source Is Nothing
          Dim DS As New DataSet
          Dim FS As FileStream
          Dim Reader As StreamReader
          Dim txtDep As CacheDependency
          Dim xmlDep As CacheDependency
          Dim aggDep As AggregateCacheDependency


          FS = New FileStream(Server.MapPath("authors.xml"),FileMode.Open,FileAccess.Read)
          Reader = New StreamReader(FS)
          DS.ReadXml(Reader)
          FS.Close()

          Source = new DataView(ds.Tables(0))
         ' Create two CacheDependency objects, one to a
         ' text file and the other to an XML file. 
         ' Create a CacheDependency array with these 
         ' two objects as items in the array.
          txtDep = New CacheDependency(Server.MapPath("Storage.txt"))
          xmlDep = New CacheDependency(Server.MapPath("authors.xml"))
          Dim DepArray() As CacheDependency = {txtDep, xmlDep}

          ' Create an AggregateCacheDependency object and 
          ' use the Add method to add the array to it.   
          aggDep = New AggregateCacheDependency()
          aggDep.Add(DepArray)

          ' Call the GetUniqueId method to generate
          ' an ID for each dependency in the array.
          msg1.Text = aggDep.GetUniqueId()
          
          ' Add the new data set to the cache with 
          ' dependencies on both files in the array.
          Cache.Insert("XMLDataSet", Source, aggDep)
          If aggDep.HasChanged = True Then
             chngMsg.Text = "The dependency changed at: " & DateTime.Now

          Else
             chngMsg.Text = "The dependency changed last at: " & aggDep.UtcLastModified.ToString()
          End If


          cacheMsg1.Text = "Dataset created explicitly"
        Else
          cacheMsg1.Text = "Dataset retrieved from cache"
        End If


          MyLiteral.Text = Source.Table.TableName
          MyDataGrid.DataSource = Source
          MyDataGrid.DataBind()
      End Sub

Remarks

This property is measured in Coordinated Universal Time (UTC) (also known as Greenwich Mean Time).

Applies to

See also